Pachylis Le Peletier & Serville, 1825

Pachylis Le Peletier & Serville, 1825: 62. — Latreille 1829: 196; 1836: 120. — Griffith & Pidgeon 1832: 218. — Laporte 1833: 25, 29. — Burmeister 1835: 300. — Brullé 1835: 353. — Herrich-Schäffer 1836: 62, plate XCII. — Spinola 1837: 38, table 7. — Voigt 1839: 373. — Blanchard 1840: 120; 1845: 441; 1847: 380. — Westwood 1840 [1839]: 482; 1842: 4; 1849: 564. — Drapiez 1842: 265. — Agassiz 1843: 14. — Amyot & Serville 1843: XXXI, 194. — Audouin et al. 1845: 36. — Signoret 1847: 301. — Herrich-Schäffer 1850: 239. — Spinola 1850: 81. — Dallas 1852: 378. — Chenu & Desmarest 1859: 213. — Dohrn 1859: 24. — Stål 1858 [1859]: 439; 1858: 29; 1862: 275; 1867: 158; 1868[1867]: 538; 1870: 131; 1873: 36. — Fauvel 1862: 275. — Costa 1868: 35. — Walker 1871: 43, 52; 1873: 32. — Uhler 1886: 10. — Lethierry & Severin 1894: 13-14. — Pittier & Biolley 1895: 15. — Kirkaldy 1900: 265; 1901: 178. — Osborn 1904: 197. — Bergroth 1913: 144. — Pennington 1920: 13. — Piza 1958: 949. — O’Shea & Schaefer 1978: 783. — O’Shea 1980: 199. — Froeschner 1981: 23; 1999: 46. — Brailovsky et al. 1994b: 319. — Schaefer & Packauskas 1997: 207. — Packauskas 2010: 176. — Brailovsky & Guerrero 2014: 365. — CoreoideaSF Team 2020. — Costa et al. 2021: 309. Thasus Stål, 1865: 174; 1868[1867]: 538; 1870: 132. — Distant 1881: 108. — Lethierry & Severin 1894: 14. — Torre-Bueno 1941: 53. — O’Shea 1980: 218. — Froeschner 1981: 23; 1988: 88. — Brailovsky et al. 1994b: 319. — Packauskas 2010: 187. — Kieran et al. 2019: 299. — Forthman et al. 2019: 528; 2020: 2. — Emberts et al. 2020: figs S2-S5. — CoreoideaSF Team 2020 n. syn.

TYPE SPECIES. — Pachylis: Cimex pharaonis Herbst, 1784, subsequent designation by Blanchard (1847) (See more information in Dolling 2010). Thasus: Pachylis acutangula Stål, 1858, subsequent designation by O’Shea (1980).

EXAMINED MATERIAL. — See Supplementary material (Appendix 1).

INCLUDED SPECIES

Pachylis acutangulus Stål, 1858 [1859] stat. rev.

Pachylis argentinus Berg, 1879.

Pachylis bipunctatus (Thunberg, 1825).

Pachylis carchinus (Brailovsky & Barrera in Brailovsky et al., (1994b)) n. comb.

Pachylis gigas Klug, 1835 in Burmeister (1835) stat. rev.

Pachylis heteropus (Latreille, 1811) stat. rev.

Pachylis laticornis (Fabricius, 1798).

Pachylis luteolus (Brailovsky & Barrera in Brailovsky et al., 1994b) n. comb.

Pachylis neocalifornicus (Brailovsky & Barrera in Brailovsky et al., 1994b) n. comb.

Pachylis nervosus Dallas, 1852.

Pachylis odonnellae (Schaefer & Packauskas in Brailovsky et al., 1994b) n. comb.

Pachylis peramplus Brailovsky & Guerrero, 2014.

Pachylis pharaonis (Herbst, 1784).

Pachylis rutilus (Brailovsky & Barrera in Brailovsky et al., 1994b) n. comb.

Pachylis tenuicornis Dallas, 1852.

Pachylis obscura Spinola, 1837 incertae sedis.

Pachylis striatus (Thunberg, 1825) incertae sedis.

DIAGNOSIS. — Robust body covered with tiny bristles; Pachylis includes the largest species of Coreidae, some specimens reaching more than 40 mm in length. Color varies from black to brown, with yellow or red spots in some species, mainly on the antennae, hemelytra, and legs. Head width less than half the pronotal width. Eye width less than half the head width; pre-ocellar tubercle absent; clypeus not elevated above the antenniferous tubercles; antennomeres I, II, and IV cylindrical, III laterally expanded, reduced in some species; apex of rostrum never surpassing the mesocoxae. Thorax with pronotum steeply declivous; pro- and mesosternum flat; male metatrochanters and metacoxae bearing a rounded spine; male metafemora expanded and robust; male metatibiae curved longitudinally, expanded and with spines on the inner margin, in some species also on the dorsal margin; male connexivum exposed, except in Pachylis acutangulus (Stål, 1858 [1859]) stat. rev. Sclerotized tooth in valvula IX, sometimes bifid as in P. gigas Klug in Burmeister, 1835 stat. rev. Coupled spermathecal pump of varying proportions, cupuliform in P. bipunctatus. Genital capsule with bifid or contiguous ventral rim; cuplike sclerite and cross bridge present but not projected; vesica straight and membranous; ductus seminis distalis twice or almost twice the phallothecal length, except in Pachylis pharaonis; disticonjunctiva with two pairs of processes, one anterior upper lateral hook-shaped, and one posterior of variable shape (rounded, sinuous or bifid) and as wide as long.

REMARKS

The diagnostic characteristics of Pachylis and Thasus are identical, with only the absence or presence of the ventral expansion in the posterior metatibiae purportedly distinguishing them (Brailovsky et al. 1994b; Brailovsky & Guerrero 2014). In the cladistic analysis the ventral expansion resulted homoplasic, not allowing for the separation between Pachylis and Thasus as suggested by previous taxonomic works (Brailovsky et al. 1994b; Brailovsky & Guerrero 2014). Therefore, the classification presented here is based on the phylogenetic results.

KEY TO THE SPECIES OF PACHYLIS LE PELETIER & SERVILLE, 1825

The present key is based on Schaefer & Packauskas (1997), Brailovsky & Guerrero (2014), and Brailovsky et al. (1994 B).

1. Humeral angles obtuse but with a small spine (if spine absent, angle obtuse) (Fig. 17A); posterior margin of pronotum with shallow median depression (Fig. 17A). Ventrally expanded metatibiae (Fig. 18A) ............... 2

— Humeral angles sharp, acuminate, sometimes with a spine (if spine removed, angle remains acuminate) (Fig. 17B); posterior margin of pronotum straight (Fig. 17B). Expanded dorsal and ventral metatibiae (Fig. 18B) ........... 8

2. Antennomeres III black, reduced expansion (less than segment width) (Fig. 18C) ....................................... 3

— Antennomeres III bicolor, lighter on basal third or median portion, of red to yellow tones, and the rest black; well-marked expansion (equals or twice the segment width) (Fig. 18D) ...................................................... 5

3. Pronotal disc with two or three dark orange or reddish longitudinal bands (Fig. 17A). Reddish brown scutellum with yellowish lateral margins, apex, and longitudinal band (Fig. 17A). Posterior margin of abdominal sternite VII without a median longitudinal fissure (Fig. 17F) .................................. Pachylis pharaonis (Herbst, 1784)

— Pronotal disc light brown and without dark orange or reddish longitudinal bands (Fig. 17C). Dark brown scutellum with lateral margins and apex dark orange, without a light longitudinal band (Fig. 17C). Posterior margin of abdominal sternite VII with a median longitudinal fissure (Fig. 17G) ......................................... 4

4. Pronotum width greater than 13.20mm (male) and 11.20mm (female). Connexival segments III-VII dark brown (Fig. 19A); posterior margin of connexival segments IV-VI with a small, wider than long spine (Fig. 19A), and male VII without spine ........................................................................ Pachylis bipunctatus (Thunberg, 1825)

— Pronotum width is less than 11.60mm (male) and 10.90mm (female). Connexival segments III-VII reddish brown with a yellowish macula in the middle third (Fig. 19B); posterior margin of connexival segments IV-VI with a large, longer than wide spine (Fig. 19B), and male VII with spine ..... Pachylis tenuicornis Dallas, 1852

5. Antennomere I light orange, black on base and apex; antennomere II light orange, black on apex (Fig. 18D) ............................................................................................. Pachylis peramplus Brailovsky & Guerrero, 2014

— Antennomeres I and II black or reddish brown (Fig. 18E) ........................................................................... 6

6. Pronotal humeral angles acute and elevated, anterolateral margins yellowish or dark orange yellow (Fig. 17D). Lateral margins of the scutellum yellow (Fig. 18B). Black femora, tibiae, and trochanters. Posterior margin of abdominal sternite VII without a median longitudinal fissure ......................... Pachylis argentinus Berg, 1879

— Pronotal humeral angles obtuse, reddish brown to black anterolateral margins (Fig. 17E). Lateral margins of the scutellum reddish brown or black, not contrasting with the disc (Fig. 17E). Femora, tibiae, and trochanters are never entirely black. Posterior margin of abdominal sternite VII with a median longitudinal fissure ...... 7

7. Clavus and corium veins yellow, contrasting with the reddish brown surface of the hemelytra (Fig. 19C). Posterior margin of pronotum markedly yellow (Fig. 17E) .................................... Pachylis nervosus Dallas, 1852

— Clavus and corium veins not contrasting with the rest of the hemelytra (Fig. 19D). Posterior margin of the pronotum not contrasting with the disc ................................................... Pachylis laticornis (Fabricius, 1798)

8. Antennomeres III dark, expansion marrow and elliptical (Fig. 18 K-M) ....................................................... 9

— Antennomeres III dark brown (Pachylis carchinus n. comb.) or bicolored, expansion broad (Fig. 18 F-J) .... 11

9. Connexival segments IV-VII dark brown, with yellow spots (Fig. 19E). Clavus and corium veins pale, contrasting with the hemelytral surface (Fig. 19E) ...................................................................................................... ............................... Pachylis luteolus (Schaefer & Packauskas, 1994 in Brailovsky et al. (1994 B)) n. comb.

— Connexival segments IV-VII dark brown to orange, without yellow spots (Fig. 19F). Clavus and corium veins not contrasting with the hemelytral surface (Fig. 19F) ............................................................................... 10